Oil heater



Nov. '21; 1944. o. c. scHAuBLE OIL HEATER Filed May 30, 1942 oooooo O O OOO www @wwf/,

INVENTQR W JM/g ATTORNEY Patented Nov. 21, 1944 l l FFICB N von; HEATER Otto CLJSchaubleQMount Kisco,`N. Y., `assigner u The LummuSCOmpany,yNew York, N\.,Y acorporation ofDelrlawm-e Y y ApinicanonMayfso, vislizfserialNo. 445,126 e fa oliniah' (rc1. `196L116) This invention relates aheater and is par` ticularly useful for furnaces in'whichdhydrocarbon oils are subjected to pyrolysis.v f It is more particularly avariation and improvement on thev constructionshown inthe patent toReed, et al., No. 2,147,609, patented .February 1.4, 1939, par.. ticularly with respect tothe useof-fewer metallic parts. ,I

'f l,With y voil 'furnaces of this ,type .'itehas become vc'onnnon to have va .heat input.y tl'ieQorderQQI 300001000 ,B- t- 11- .per hounlns @furnace Qf. this type will customarily mhav tubes.,yirllkiihe@ifj'ofl the ordm'. of 20 top40; jfee'tinlengthsurpcrted around the Walls of a chamber Whichwigll bev of ltheorde'r of 20 feet ,'squarecrsssxction,"the'tubes being of the order of '21/"` to -5v-in diameter. The Weight of lthejtubs is, very substantial; with the temperature A'in the f combustion *zone varying from 3,000 atthe' burner rto `a` gas' outlet temperature of around 1,400 F.'fr0m-the use .tubeV supports of a nigh quality; 'heauressti ant alloy. In generalfit is" considered necessary overhead structural vsupports may be materially .reduced in size. t x

A -stiu further object 'ofy thfmvention is tov i provide an improved arrangement of an oil heater radiant section,"it*ha's beenl found neessa3;fto

at 'this tinfie'to use alloy steel castings 'containj 'ing approximately' 25% "chromiuinfand 112% nickel for temperature fser'vice above"1,400'" F. The Weight of the tube support castingsisfin the orderof-loto :12wpou'nds per tube supported, and the total WeightA ofl castings asfwelliasthe cost is thus veryisubstantialr; L 'I n 'Itis not onlydesirable tofelimin'ate'the ex"- pense of'thesecastingsjbutg at the` present time,

'due to war emergency, it" has'ibecome-increas'a,

ingly diilicult to obtain the Achrcmiiuni"ar'i'dfth nickel, andeiorts have. ybeer'i'made" torr nol'y `a substitute which wmp@ sobs-tantialiy as eireetive 'and which will use less metal of the high quality ttypel However, with average temperatures from 1,400" F. to'2,100 it is substantiallyimpos I Areceive thelheat-receiving elements `so that re; moval and replacement: are readily accomplished.

l Another objectfof the. inventionisl to provide sible Without heat-resisting .alloysto reducethe lin which a@ plenum chamber is mounted below the radiant ysection .'With an intermediate rowv l otradiantv tubes` extending across the gas ,exitA from the radiant section, such radianttubes and plenum chamber .aidingtof'distribute 'the flowl of gases uniformlyacrossthegasiexitk vFurther objects andv advantages of myinvention will appear `fronfr-fthefollowing description of a preferred form of 'embodiment thereof taken in connectionl with wthef-attached drawing, in which?` f j fFig.1 is asubstantiallygcentral vertical cross section rthrough the improved-formv o f heater; "Fig, 2 isaperspective view of a detail ;of-the lower part of'thezfurnacei j' a Fig. 3'is a detail cross section ofk the-tube support, andi,- x* v ligml` isa detail cross section showing a modified form of tube support;4

In accordance 'with mypresent preferred arrangement of furnacepforthe radiant heating ofoil tubes is shown'inv theattached drawing, it being understoodv that the principles disclosed maygbe` applied ,to different'forms of lconstruction-and thatthe chambers of the furnace may. be made in pairs or otherwisadepending upon the number of-units and the nature vof operations to' be carried out. The' simple form of furnace IIJ shownv consistsprimarily of a radiant section I.I,iny whichjuel is burned by burnried bythe ceiling' beams",l [6 through ,suitable hangars I'l. It is, of` course, to beV understood kthat the roof isu'sually made in a plurality of van improved arrangement of the radiant and convvection sections ofan oil heater in whicha greater proportion of the loadof thetubes is ,carried directly .by the,ffoundation .s0that-,a .smaller amount. of valloy metal islfused. and `so that the rovided. ,45 p

sections and necessary expansion jointswill be 'Il'ne'r'adianty sectic'rnnl'l.r isprovided with side Walltubes I'8,Which` are of'a desired'size and thro'ugh? which o'il'is passedinfa desired flow `path. Customarily,"the sidewall banks I8 and Ia'will beconnected in series with the'oil intro'- duced at suitable'points for the desired heating effect- In addition, the radiant sectionl is providediwth at leastonerow of tubes I9 extending substantially across thegas exit opening from the radiant section. If'desired, a second row I9a 'may Lalso be vuse d,.and in such case they will invention, one

serve as diffusion 'baiiies to aid in prevention of channeling of the discharge gases, as hereinafter pointed out.

The products of combustion pass across these tubes into the plenum` chamber 2| and thence through arches 2| a to the convection section 22, which is provided with a bank of tubes 23 for preheating y,of oil..,or for the generationv ofA steam. or for other l1Owerftemperature operation so'that the products of combustion ultimately' discharge at 25 to the stack at a minimum temperature` l.

consistent with good engineering practice.

and through the channels of the plenum chamber 2l to the confined convection section 22.

Suitable refractory for the radiant section can be first-quality or super-duty refractory clay brick or special shapes. They are built in pilaster formation to form the supports for the tubes at the intermediate points.

. 'Withthe lower. temperatureinthe. convection section, it is possible to use:` customary 'cast iron or low chrome tube supports, and in view of the restricted cross section, the metal supports would be preferred, but such material is not suit- A furnace of this type is customarily supported4 f on concrete foundations or piers 28, .between Y.

which extend floor beams, 29'. steel beams 30 extending above thepiers 28'carry The structural 'able for use in the combustion zone as there is no .knownrsubstitute for the high chrome, high ,nickel',. heateresisting alloy to withstand the radiant` chambentemperatures.

the ceramic side walls 32 and the insulating medium 34 and the supporting-plates aswell Suitable Y' panel wall constructions are more particularly'l as the roof I4 and upper beams I6.

means, as distinguished from vthe typical alloyV castings heretofore used. As will appear from Fig.' 2, transverse and vertical piers or pilasters 3l;n are builtacross the floor 311 and up `the side walls32, and such piers are preferably of standard refractory 38, the brick inione example being approximatelylZl/z" hi'gh by 9 long by i1/ 2 wide. It is possible to build the desiredv` size of pier with such ceramic units and with'. special shapes 39. These latter may haveopenings 39a;

, in Whichthe tubes l'and I'Smay'be" supported,

or spaces may beY left. between the standard shapes 38, as shown in 4;k Noothersupport for'the tubes is' required. If' desired, however,

the openingsmay be r` provided with. flat plates' 40 v to'facilitate movementl during expansion ofthe i tubes. These may "be" of" a'high chrome, high nickel alloy, but theamou'nt'of metal is relatively small. l I l Preferably, the'vertical portions ofthe piers 36 may be tapered toward the' top; It will be apparent'that'the. load is least' at thetop and the minimum ofA material is 'necessary for the desired support. Preferably,the piers 3.61also extend as vertical abutments 3'6'0l transversely across the bottom ofthe radiantsection and', asfshown in Fig. 2, these piers arey vspacedat suitable inter.- vals, as, for exaniple,.six.feet aparty p The ceramic, piers or pilasters, together, with the transverse supports for the horizontal` bank of tubes, providesl an entirelysubstanti-al support with noappreciable amountI of metal. The openings can be arrangedto permit the insertion of the tubes. from the-ends of the furnace, and, as the: loadt'is carried directly to the foundations,A there is no 1appreciableV variation in shape or location under heat;

The combustion of them-e1 within the. radiant section ist notsmai-:eriaally` impeded' bythe transverse projections ot. these. piers, for the flow: of gas is downward and aat a relatively low' velocity I have also found an unexpected advantage in thisl arrangement of furnace, in which the horizontallbanl; of tubes is placed across the gas exit opening at the bottom of the chamber. 1It is noty only notnecessarytoshieldthese tubes, but

' it isf possible to obtain` a highlyfdesirable baiing arrangement,l whichvtends to prevent channeling of: the gases from theradiant'zone. This improves theblanlreting4 effector the gases on the sidefwalltubesl and reduces the' convection effect, which might otherwise be objectionable'.

As previously pointed out, a secondlrow of 'tubes I8'a below theinrstrow and. spaced'therebetween can be used.' with. advantage, not only from the standpointo additionallheat input, but also to further. reduce channeling effectsand to reduce theintertuberea Asothattheaggregate-flow area is. lessthan. the Iaggregate intertube area of the portions of theftubes'intherstrow. It will, of course, tbe appreciated that suitable tile, as shown in Zimmerman patent, No. 2,147,610, could be used in lieu of the-second row of tubes or in addition tothem; 1 i f Y' While/'I haveshown a preferrediform of embodiment of my finvention, 4.I unaware that modifications maybe made thereto; I, therefore, desirea broad interruption` of.: my Airrventioi'n within the'scez'apeA and: spirit-of thedescription' herein and of the claims appendedhereinafter;

l.. An oil heater'includingfa'housing defining a radianti heating' clian'xbe'r` and' a. plenum chamber beneath said heating chamber; andwith a gas exit from'theb'ottom ofzthe'heating chamber to the'plenum chamber, saidhousingihaving opposite vertical' inner" side walls, vertical banks of horizontailylarranged' oil-'heating tubes at said sidewalls and with thetubes of said banks vertically' spacedpver thc-areas of thev respective side walls; a horizontal. bank. of.-.horizontally arranged oil-heating tubesy transversely spaced in a series between the lower ends of said vertical banks and extending4 across .said gasy exit, burner means for fuel combustion within said heating chamber to heat the tubes. of said: vertical and horizontal banks by radiant. heat, vertical., ceramic pilasters on. said side walls andintegrated. therewith respectivelyV and. located intermediate the ends of said tube banks and. in oppositionto each other across the interior of the housingandA providing support for the'. tubes of' said vertical. banks, and a ceramic bridge within the plenum chamber and extending between the lower end portions of the opposed pilasters and continuous therewith and affording` intermediate under support for the tubes of'said horizontal bank, the opposed pilasters' and bridge together forming a U-shaped structure supported at its oppositeu sides by said side walls and at its base by the bottom of the housing. 1

2. In a. fluid heater including a housing definingy I bustion within said chamber; `vertical banks of horizontally arranged duid-heating tubes at said side walls and with the tubes of said banksver-r tically spaced over the areas of the respective sidev Walls, a horizontal bank of horizontally arranged duid-heating tubes transversely spaced in a series between the lower ends of said vertical banks and extending across said gas exit, vertical ceramic y `pilasters on said side walls and integrated there- Lwith respectively and located intermediate thel ends of said tube banks and in opposition t0 each other across the interior 0f the housing and providingy supporty for the tubes of 'said vertical banks, `and a ceramic bridge extending betweenthe lower end portions of the opposed'pilasters and continuous therewith and affording intermediate under'support for the tubes of` said horizontal bank, the opposed pilasters and bridge together forming a U-shaped structure supported at its opposite sides by said side Walls and at its base by the-bottom .of the housing.

` OTTO C, SCHAUBLE. 

